Cuba holds an unbeatable world record in terms of ''rolling gems'' - in no other country in the world do so many dinosaurs of car history rattle and roar through the streets. The whole island is a kind of Jurassic Park for a special kind of dinosaur - candy pink, sky blue, sun yellow or squeaky green painted Chevrolets, Buicks, Chryslers, Fords, Plymouth or Studebakers, and Havana is the classic car hotspot.